Electro-hydraulic power vehicle-brake system for an autonomously driving land vehicle

Abstract

An electro-hydraulic power vehicle-brake system for a motor vehicle autonomously driving on public roads. A secondary brake unit is connected to a service brake unit so that in the event of a failure of the service brake unit, the vehicle brake system is able to be actuated using the secondary brake unit. In order to be able to rapidly build up a brake pressure with the aid of the secondary brake unit even with a cold and viscous brake fluid, brake fluid reservoirs are provided that are integrated into the secondary brake unit and are connected by short line lengths to hydraulic pumps of the secondary brake unit.

What is claimed is: 
     
         1 . An electro-hydraulic power vehicle-brake system for a land vehicle autonomously driving on a public road, comprising:
 at least one hydraulic wheel brake;   a service brake unit to which the at least one hydraulic wheel brake is connected and including a brake pressure generator for generating a brake pressure;   a brake-pressure control valve array for controlling a wheel brake pressure acting on the at least one hydraulic wheel brake;   a service brake unit; and   a secondary brake unit connected to the service brake unit so that in the event of a failure of the service brake unit, the at least one hydraulic wheel brake is able to be actuated using the secondary brake unit, wherein:
 the secondary brake unit includes a power brake pressure generator for generating a brake pressure applied to the at least one hydraulic wheel brake, and 
 the secondary brake unit includes a brake fluid reservoir integrated into the secondary brake unit and to which the power brake pressure generator of the secondary brake unit is connected so that the power brake pressure generator of the secondary brake unit is able to aspirate brake fluid from the brake fluid reservoir in order to generate the brake pressure. 
   
     
     
         2 . The electro-hydraulic power vehicle-brake system as recited in  claim 1 , wherein the secondary brake unit includes an hydraulics block in which the brake fluid reservoir is situated. 
     
     
         3 . The electro-hydraulic power vehicle-brake system as recited in  claim 1 , wherein the power brake pressure generator of the secondary brake unit is connected to the brake fluid reservoir by a line that is at least one of short and straight. 
     
     
         4 . The electro-hydraulic power vehicle-brake system as recited in  claim 1 , wherein the brake fluid reservoir is nonpressurized. 
     
     
         5 . The electro-hydraulic power vehicle-brake system as recited in  claim 1 , wherein the secondary brake unit includes one of a piston-cylinder unit, a bellows reservoir, and a diaphragm reservoir as a brake fluid reservoir. 
     
     
         6 . The electro-hydraulic power vehicle-brake system as recited in  claim 1 , wherein at least one of the power brake pressure generator and the brake fluid reservoir of the secondary brake unit is connected to at least one of the brake pressure generator and a brake fluid reservoir of the service brake unit. 
     
     
         7 . The electro-hydraulic power vehicle-brake system as recited in  claim 1 , wherein at least one of:
 a suction side of the power brake pressure generator of the secondary brake unit is connectable via a first valve to at least one of the brake pressure generator and the brake fluid reservoir of the service brake unit, and   a pressure side of the power brake pressure generator of the secondary brake unit is separable by a second valve from at least one of the brake pressure generator and a brake fluid reservoir of the service brake unit.   
     
     
         8 . The electro-hydraulic power vehicle-brake system as recited in  claim 1 , wherein:
 the secondary brake unit includes a charge and check valve, by which the brake fluid reservoir of the secondary brake unit is connected to at least one of the power brake pressure generator of the secondary brake unit and the brake pressure generator of the service brake unit, so that at least one of the power brake pressure generator of the secondary brake unit and the brake pressure generator of the service brake unit is able to convey brake fluid into a brake fluid reservoir of the secondary brake unit.   
     
     
         9 . A method for at least one of charging and evacuating a brake fluid reservoir of a secondary brake unit, comprising:
 opening a charge and check valve; and   at least one of charging and evacuating the brake fluid reservoir of the secondary brake unit using a one of brake pressure generator of a service brake unit and a power brakepressure generator of the secondary brake unit.   
     
     
         10 . The method as recited in  claim 9 , further comprising evaluating the at least one of the charging and evacuating.